Consider the following pairs:

Types of Chemical Weathering	Characteristics
I. Solution	Results in leaching of minerals
II. Carbonation	Helps in breaking down feldspars
III. Hydration	Causes an increase in the volume of rocks
IV. Oxidation	Changes the colour of rocks

How many pairs given above are correctly matched?

Chemical weathering processes include solution, carbonation, hydration, and oxidation.

I. Solution involves the dissolution of soluble minerals in water or weak acids, leading to the leaching of minerals from rocks. This pair is correctly matched.

II. Carbonation is the reaction of carbonates and bicarbonates with minerals. It is a common process that helps in the breaking down of feldspars and carbonate minerals. This pair is correctly matched.

III. Hydration is the chemical addition of water. Minerals absorb water and expand, causing an increase in the volume of the rocks, which leads to physical stress. This pair is correctly matched.

IV. Oxidation involves the reaction of minerals with oxygen to form oxides or hydroxides. This process often changes the colour of rocks, such as iron-bearing minerals turning red, brown, or yellow upon oxidation. This pair is correctly matched.

All four pairs are correctly matched.

Answer: All the four